A long sought after goal is to provide a disposable diaper, sanitary napkin, bandage, and the like which indicates the presence of bodily excretion while at the same time precluding subjecting the body to deleterious effects of substances present in the excretion indicating system. The following four representative prior art patents all provide for bodily excretion-indicating disposable articles using color-indicating, moisture-activated water soluble or dispersible dyes or food colorings: U.S. Pat. No. 3,675,654 of Baker et al; U.S. Pat. No. 3,918,454 of Korodi et al; U.S. Pat. No. 3,952,746 of Summers; and U.S. Pat. No. 4,022,211 of Timmons et al.
One problem associated with such prior art systems is as follows: though the water soluble or dispersible color indicating substances are disclosed as being nontoxic, it is well known that as the sciences of pharmacology and toxicology advance, numerous substances and exposure limits previously regarded as harmless or safe are thought of in a new light with respect to their toxicity. This being the case, reluctance may be felt to subject the body to any unnecessary repeated contact with water soluble or dispersible chemicals.
A second problem associated with the bodily excretion indicating systems of the prior art is their dependence upon moisture alone for their activation. Undesired activation may occur in areas of high humidity or when the disposable article may undergo inadvertent temperature and humidity cycling such as initial exposure to a high temperature-high humidity environment (such as summer storage) with subsequent exposure to a cold environment (e.g. winter storage) with consequent moisture condensation.
In view of the above deficiencies and inadequacies of the prior art in bodily excretion indicating disposable articles, it is an object of the present invention to provide a disposable article which indicates the presence of bodily excretions without employing water soluble or dispersible coloring agents.
Another object of the invention is to provide a bodily excretion indicating disposable article whose indicating system does not depend solely on the moisture component of the excretions.
Another object of the invention is to provide a disposable article for absorbing bodily excretions having a moisture absorbent saline water indicating material.
Another object of the invention is to provide a disposable article having a saline water indicating article having as a component a water insoluble polymeric acid-base indicator whose range of pH change can be outside the pH range of bodily excretions.
These and other objects are accomplished by the invention as described below.